I guess the real question is, why do you want the snap-in adapter anyway?

The snap-in adapter has one significant upside over just using the standard USB port and a white Apple cord (iPod Out) and a few significant downsides (trapping phone in armrest, no audible text alerts, no split-screen, etc.).

Most of us deal with the loss of the Apple user interface and adapt to the BMW interface very quickly, and the upsides of not having to jail the iPhone in the armrest and gaining split-screen for our iTunes collections are more important.

We debated this months ago here, screenshots of the varying music screens for reference: